A polymerization kettle for preparing high molecular weight PIPD polymer and a method for preparing PIPD polymer

Abstract

The present application relates to the polymerization technology of high performance polymer PIPD, and discloses a polymerization kettle for preparing high molecular weight PIPD polymer and a preparation method of the PIPD polymer.The polymerization kettle comprises a polymerization kettle body and a stirring paddle arranged in the polymerization kettle body; the stirring paddle comprises a stirring shaft, a prismatic flat paddle, a folded paddle and a spiral paddle; the stirring shaft is vertically arranged, the prismatic flat paddle and the folded paddle are fixed on the stirring shaft from top to bottom and are arranged along the radial direction of the stirring shaft; and the spiral paddle is arranged in a spiral structure around the folded paddle with the stirring shaft as the central shaft.The polymerization kettle and the stirring paddle disclosed by the present application are suitable for the polymerization reaction characteristics of high rigidity PIPD polymer, can effectively and uniformly blend in the early, middle and late stages of the polymerization reaction, greatly reduce the mixing dead zone in the polymerization kettle, improve the mass transfer and heat transfer efficiency in the polymerization process, and obtain high molecular weight PIPD polymer in a short time (<12h).

Description

Technical Field

[0001] This invention relates to polymerization technology of high-performance polymer PIPD, specifically to a polymerization reactor for preparing high molecular weight PIPD polymer and a method for preparing PIPD polymer. Background Technology

[0002] Poly(2,5-dihydroxy-1,4-phenylenepyridinediimidazole) fiber (PIPD), as a high-performance organic fiber with outstanding comprehensive properties, has great application potential in ballistic protection and aerospace fields. High-strength, high-modulus PIPD fibers require high-molecular-weight PIPD polymer spinning solutions to be prepared through a dry-jet wet-spinning process. The inherent high rigidity of the PIPD molecular chain, resulting in high viscosity, poses significant challenges to mass and heat transfer in the later stages of polymerization, representing a major difficulty in the preparation of high-strength PIPD fibers.

[0003] There are two main polymerization routes for PIPD: 1) Traditional two-component monomer polymerization, i.e., tetraaminopyridine hydrochloride and 2,6-dihydroxyterephthalic acid (DHTA), uniformly blended in polyphosphoric acid after removing hydrochloric acid gas, and then subjected to gradient heating; 2) Preparing a TD complex salt (TAP:DHTA = 1:1) using tetraaminopyridine hydrochloride and 2,6-dihydroxyterephthalic acid, and then using this TD salt as a monomer in polyphosphoric acid for polymerization. Regardless of the process route, the preparation of high molecular weight PIPD polymers is crucial for obtaining high-strength, high-modulus, high-performance PIPD fibers. As a rigid rod-shaped polymer structure, the rigidity of the molecular chains in PIPD polymers results in extremely high polymerization viscosity in the later stages of polymerization. Effectively improving the mass and heat transfer efficiency of the polymerization system is a major challenge in the preparation of high molecular weight polymers.

[0004] For high-rigidity PIPD polymers, traditional processes use a twin-ribbon impeller as the agitator in the polymerization reactor. The twin-ribbon impeller utilizes the polymer's climbing effect and the high specific surface area of ​​the ribbons to spread the polymer along the impeller surface, which is beneficial for mass and heat transfer in the later stages of high-viscosity polymerization. However, as a commonly used impeller for high-viscosity polymerization systems, the twin-ribbon impeller has a large area of ​​voids in its central region. Mixing the material within these voids requires the ribbon impeller to drive the relative movement of the surrounding material for dissolution and mixing. This is ineffective for pastes, low-viscosity slurries, and low-viscosity, easily shearable materials. However, in the early stages of PIPD polymerization, powdered monomers and the dehydrating agent phosphorus pentoxide are dissolved in the polymer solvent polyphosphoric acid, forming a paste at low temperatures (<100). oC). Its high solids content (18%-22%) and poor flowability of polyphosphoric acid at room temperature, coupled with its tendency to shear (to avoid auto-initiation of polymerization at high temperatures, initial mixing is mostly done at room temperature), make it difficult for the solid components to mix uniformly in the polyphosphoric acid during the early stages of polymerization, resulting in multiple heterogeneous mixing dead zones in the reactor. After heating, the degree of polymerization becomes difficult to control effectively. Furthermore, the significant polymer climbing effect in the later stages of polymerization causes accumulation at the top of the agitator. Due to the small gap between the ribbon impeller and the reactor body, it is difficult for the polymer to effectively return to the middle and bottom of the polymerization reactor by its own weight, thus hindering effective mass transfer.

[0005] Therefore, traditional twin-ribbon agitators cannot meet the requirements of high molecular weight PIPD polymers and high molecular weight polymer spinning solutions, resulting in low strength and modulus of the prepared PIPD fibers, which cannot meet application requirements. Further improvements are urgently needed to improve the preparation process. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems, the main objective of the present invention is to provide a polymerization reactor (also known as a polymerization reaction vessel) for preparing high molecular weight PIPD polymer and a method for preparing PIPD polymer using the polymerization reactor.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a polymerization reactor for preparing high molecular weight PIPD polymer, comprising a polymerization reactor body and a stirring impeller disposed within the polymerization reactor body, characterized in that the stirring impeller comprises a stirring shaft, a prismatic flat blade impeller, a folding blade impeller, and a ribbon impeller. The stirring shaft is vertically arranged. The prismatic flat blade and the folding blade are fixed to the stirring shaft from top to bottom and extend radially along the stirring shaft. The spiral blade is arranged in a spiral structure with the stirring shaft as the central axis and is located around the folding blade. The upper and lower ends of the spiral blade are connected to the stirring shaft through an upper fixed rod blade and a lower fixed rod blade, respectively. The upper fixed rod blade is located between the prismatic flat blade and the folding blade, and the lower fixed rod blade is located below the folding blade. The prismatic flat blade is a square cylinder with its cylindrical surface inclined relative to the plane of rotation; the folding blade is a sheet-like blade with its blade surface forming an angle of 40-60 degrees with the plane of rotation. As a further preferred technical solution of the present invention, the polymerization reactor also includes a power drive mechanism, which is connected to the stirring shaft to replace the rotation of the stirring shaft.

[0008] As a further preferred technical solution of the present invention, the prismatic flat blade has multiple blades, and the multiple prismatic flat blades are evenly distributed in the same plane of rotation.

[0009] As a further preferred embodiment of the present invention, the folding blade has multiple sets, and the multiple sets of folding blades are distributed at intervals and staggered along the axial direction of the stirring shaft.

[0010] As a further preferred technical solution of the present invention, the ribbon impeller has multiple sets, and the multiple sets of ribbon impellers are arranged in a rotationally symmetrical manner with the stirring shaft as the central axis.

[0011] As a further preferred technical solution of the present invention, there are three prismatic flat blades, which are evenly distributed on the same plane of rotation, and the included angle between adjacent prismatic flat blades is 120 degrees; there are three sets of folding blades, which are distributed at intervals and staggered along the axial direction of the stirring shaft, with a staggered angle of 120 degrees; there are three sets of spiral blades, which are arranged in a rotationally symmetrical manner with the stirring shaft as the central axis.

[0012] As a further preferred technical solution of the present invention, the inner cavity of the polymerization reactor body is a cylinder with an inner diameter of Dr and a depth of H. Then: the outer diameter of the circle formed by the motion trajectory of the spiral propeller when it rotates is 0.85-0.90 Dr, the height of the spiral propeller is 0.8-0.85H, and the blade width of the spiral propeller is 0.05-0.15Dr; the diameter of the circle formed by the motion trajectory of the folding blade propeller when it rotates is 0.6-0.7Dr, and the blade width to length ratio of the folding blade propeller is 0.12-0.22; the spacing between the three layers of folding blade propellers is 0.20H, and the spacing between the uppermost folding blade propeller and the upper fixed rod propeller is 0.1H; the diameter of the circle formed by the motion trajectory of the prismatic flat blade propeller when it rotates is 0.4-0.5Dr, and the blade width to length ratio of the prismatic flat blade propeller is 0.18-0.25; the spacing between the upper fixed rod propeller and the prismatic flat blade propeller is 0.15H.

[0013] According to a second aspect of the present invention, the present invention also provides the application of the polymerization reactor for preparing high molecular weight PIPD polymers using the method of the first aspect in the preparation of high molecular weight PIPD polymers.

[0014] According to a second aspect of the present invention, the present invention also provides a method for preparing a high molecular weight PIPD polymer, which uses a polymerization reactor for preparing a high molecular weight PIPD polymer according to the first aspect, specifically including the following steps: TD salt, phosphorus pentoxide, and polyphosphoric acid were added to the polymerization reactor, along with tin powder as an initiator. The stirring paddle was started under an inert atmosphere, and the reaction was carried out by stirring in stages with increasing temperature. After the reaction was completed, stirring was stopped, and the polymer was removed from the reactor.

[0015] As a further preferred technical solution of the present invention, the stirring reaction is carried out by staged heating, specifically as follows: stirring at room temperature for 10 to 30 minutes, heating to 100°C and reacting for 0.5 to 1 hour, then heating to 140°C and reacting for 1 to 2 hours, continuing to heat to 180°C and reacting for 1 to 2 hours, and finally cooling to below 120°C and stopping stirring. The stirring rate is set as follows: 350~250 r / min for room temperature to 100℃; 160~240 r / min for 100-140℃; and 120~150 r / min for 140-180℃.

[0016] The principle of the polymerization reactor for preparing high molecular weight PIPD polymers in this invention is as follows: The PIPD polymerization reaction involves dissolving powdered monomers in polyphosphoric acid at a specific solid content, followed by two processes: amidation and high-temperature dehydration cyclization. In the early stage of amidation, the degree of polymerization is low, and the system exhibits a low-viscosity paste-like consistency, making it easy to cut. As the degree of polymerization increases, the viscosity gradually increases. During the high-temperature cyclization process, the polymer's molecular chain conformation straightens completely along with the degree of aromatization, and the apparent viscosity increases rapidly. Both processes generate one molecule of water; therefore, a certain amount of dehydrating agent is beneficial for the forward reaction. The polymerization reaction targeted is for the high-rigidity polymer PIPD. Therefore, the three parts of the stirring paddle in this invention—the prismatic flat blade paddle, the folding blade paddle, and the ribbon paddle—are indispensable, covering the entire process of high-rigidity polymer polymerization. The central folding blade and the outer ribbon blade create relative motion, ensuring effective and uniform blending of powdered monomers, desiccant, and polymer solvent in the early stages of polymerization. This significantly reduces the probability of monomers clumping together due to solvent encapsulation. In the later stages of polymerization, as polymer viscosity increases dramatically, the ribbon blade's agitation allows the polymer to spread along the blade surface, improving mass and heat transfer. The upper prismatic blade, with its specific prismatic structure and increased distance between the blade tip and the reactor wall, quickly and efficiently throws polymers climbing the rods in the later stages of polymerization onto the reactor wall via centrifugal force, achieving effective material blending.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) The polymerization reactor and stirring paddle shape disclosed in this invention are designed for the polymerization reaction characteristics of high rigidity PIPD polymer. They can effectively and uniformly blend the polymer in the early, middle and late stages of the polymerization reaction, greatly reduce the mixing dead zone in the polymerization reactor, improve the mass transfer and heat transfer efficiency during the polymerization process, and obtain high molecular weight PIPD polymer in a short time (<12h).

[0018] (2) The PIPD polymer prepared by this technology has a higher molecular weight, and can obtain nascent fibers with higher mechanical strength (>4 GPa) in the subsequent fiber forming process, and has better prospects for fiber preparation and application. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram of the overall structure of the polymerization reactor in Embodiment 1 of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the stirring paddle in Embodiment 1 of the present invention.

[0022] Figure 3 A perspective view of the stirring paddle in Embodiment 1 of the present invention.

[0023] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0026] Example 1 like Figure 1 As shown, this embodiment provides a polymerization reactor for preparing high molecular weight PIPD polymer, including a polymerization reactor body 100 and a stirring paddle 200 disposed inside the polymerization reactor body 100. The upper part of the polymerization reactor body is open and has a reactor cover. A motor 101 is mounted on the reactor cover. The drive shaft of the motor 101 passes through the reactor cover and extends into the interior of the polymerization reactor body 100 and is connected to the vertically arranged stirring paddle 200. In addition, the top of the polymerization reactor body 100 is provided with an air inlet 102 and an air outlet 103, and the bottom is provided with a discharge outlet 104.

[0027] like Figure 2 and Figure 3As shown, the agitator 200 includes an agitator shaft 201, a prismatic flat blade impeller 204, a folding blade impeller 203, and a ribbon impeller 202. The prismatic flat blade impeller 204 and the folding blade impeller 203 are fixed to the agitator shaft 201 from top to bottom and extend radially along the agitator shaft. The ribbon impeller 202 is arranged in a spiral structure with the agitator shaft 201 as the central axis and is located around the folding blade impeller 203. The upper and lower ends of the ribbon impeller 202 are connected to the agitator shaft 201 by an upper fixed rod impeller 205 and a lower fixed rod impeller 206, respectively. The shaft 201 is connected, wherein the upper fixed rod paddle 205 is located between the prismatic flat blade paddle 204 and the folding blade paddle 203, and the lower fixed rod paddle 206 is located below the folding blade paddle 203; the prismatic flat blade paddle 204 is a regular square prism, and its prism surface is inclined at 45 degrees relative to the plane of rotation; the folding blade paddle 203 is plate-shaped, and its blade surface forms an angle of 40-60 degrees with the plane of rotation, and the angle of the folding blade paddle 203 is opposite to the angle of the ribbon paddle 202, ensuring that the material at the center position can be effectively mixed.

[0028] There are three prismatic flat blades, which are evenly distributed on the same plane of rotation, with an included angle of 120 degrees between adjacent prismatic flat blades; there are three sets of folding blades, which are distributed at intervals and staggered along the axial direction of the stirring shaft, with a staggered angle of 120 degrees; there are three sets of spiral blades, which are rotationally symmetrical about the stirring shaft as the central axis and can overlap after rotating 120 degrees. In this embodiment, the polymerization reactor uses a 1L reactor body, and the designed stirring paddle is used in conjunction with the 1L reactor body. The inner cavity of the polymerization reactor body is cylindrical, with an inner diameter of Dr and a depth of H. Correspondingly: the outer diameter of the circle formed by the motion trajectory of the ribbon paddle when rotating is 0.85Dr, the height of the ribbon paddle is 0.8H, and the blade width of the ribbon paddle is 0.08Dr; the diameter of the circle formed by the motion trajectory of the folding blade paddle when rotating is 0.6Dr, and the ratio of blade width to folding blade length is 0.12; the spacing between the three layers of folding blade paddles is 0.20H, the spacing between the uppermost folding blade paddle and the upper fixed rod paddle is 0.1H; the spacing between the upper fixed rod paddle and the prismatic flat blade paddle is 0.15H; the diameter of the circle formed by the motion trajectory of the prismatic flat blade paddle when rotating is 0.4Dr, and the ratio of blade width (horizontal direction) to prismatic flat blade length is 0.18.

[0029] Example 2 This embodiment provides a method for preparing a high molecular weight PIPD polymer, which uses the polymerization reactor of Example 1. The specific preparation method is as follows: 61.16 g of 2,3,5,6-tetraaminopyridine-2,5-dihydroxyterephthalate (TD salt), 39.45 g of phosphorus pentoxide, and 167.18 g of polyphosphoric acid were added to the polymerization reactor, along with 320 mg of tin powder as an initiator. After purging with argon three times, the motor was started to drive the stirrer, and the reaction was carried out in stages with increasing temperature. Specifically, the stirring was carried out at room temperature for 30 min, then the temperature was increased to 100℃ for 1 h, then increased to 140℃ for 2 h, and then increased to 180℃ for 2 h. The polymerization reaction was then stopped, and the temperature was lowered to 120℃ before stirring was stopped. The stirring rate was set as follows: 300 r / min from room temperature to 100℃; 200 r / min from 100 to 140℃; and 150 r / min from 140 to 180℃.

[0030] The reaction system was cooled to room temperature, and 300 mL of water was added. After the polyphosphoric acid was completely absorbed and decomposed, anhydrous sodium carbonate was added to adjust the pH to 7. Then, the precipitated polymer was washed with water, dried, and the intrinsic viscosity of the polymer, which reflects the degree of polymerization, was measured using an Ubbelohde viscometer. The intrinsic viscosity was found to be 31.2 dL / g.

[0031] TD salts can be commercially purchased or prepared in the laboratory. In this embodiment, TD salts are prepared by acid-base neutralization reaction of 2,3,5,6-tetraaminopyridine hydrochloride and 2,5-dihydroxy-1,4-terephthalic acid. For details, please refer to the preparation method disclosed in Chinese Patent No. CN116969883B entitled "A Continuous Preparation Method of High Purity 2,3,5,6-Tetraaminopyridine-2,5-dihydroxyterephthalic Acid".

[0032] Comparative Example 1 As a comparative experiment to Example 2, the only difference from Example 2 is that, based on the polymerization reactor of Example 1, the prismatic flat blade and folding blade impellers of the agitator were removed, leaving only the ribbon impeller. Finally, the intrinsic viscosity of the polymer, reflecting the degree of polymerization, was measured using an Ubbelohde viscometer, and the obtained intrinsic viscosity was 25.6 dL / g.

[0033] Comparative Example 2 As a comparative experiment to Example 2, the only difference from Example 2 is that, based on the polymerization reactor of Example 1, the prismatic flat blade impeller and the ribbon impeller of the agitator were removed, leaving only the folding blade impeller. Finally, the intrinsic viscosity of the polymer, reflecting the degree of polymerization, was measured using an Ubbelohde viscometer, and the obtained intrinsic viscosity was 15.3 dL / g.

[0034] Comparative Examples 1 and 2, using only a single propeller type, failed to achieve the polymerization effect of the three-propeller combination (prism-shaped flat blade propeller, folding blade propeller, and ribbon propeller) in Example 1. Compared to Example 1, retaining only the ribbon propeller reduced the intrinsic viscosity to 25.6 dL / g, while retaining only the folding blade propeller resulted in a significant reduction to 15.3 dL / g. This indicates that PIPD polymerization is a high-viscosity system, and a single propeller type cannot simultaneously achieve both overall system cyclic mixing and localized mass transfer. Inhomogeneous mixing significantly limits the growth of polymer molecular weight. Furthermore, the folding blade propeller is suitable for low- to medium-viscosity systems, and its ability is severely insufficient when used alone for high-viscosity PIPD polymerization.

[0035] Comparative Example 3 As a comparative experiment to Example 2, the only difference from Example 2 is that, based on the polymerization reactor of Example 1, the prismatic flat blade impeller of the agitator was removed, while the folding blade impeller and the ribbon impeller were retained. Finally, the intrinsic viscosity of the polymer, reflecting the degree of polymerization, was measured using an Ubbelohde viscometer, and the obtained intrinsic viscosity of the polymer was 27.3 dL / g.

[0036] Compared to Comparative Examples 1 and 2, Comparative Example 3, which removed the prismatic flat-blade impeller but retained the folded-blade impeller and ribbon impeller combination, increased the intrinsic viscosity of the product to 27.3 dL / g, significantly better than the single impeller type, but still lower than the 31.2 dL / g of the three-impeller combination. This indicates that the ribbon impeller + folded-blade impeller can achieve better mixing than a single impeller, but the lack of the prismatic flat-blade impeller still results in a loss of some polymerization performance.

[0037] Comparative Example 4 As a comparative experiment to Example 2, the only difference from Example 2 was that, based on the polymerization reactor of Example 1, the prismatic flat blade impeller was replaced with a cylindrical one (the length of the cylinder was the same as that of the prismatic flat blade impeller in Example 1, and the ratio of diameter to length was 0.18). Finally, the intrinsic viscosity of the polymer, reflecting the degree of polymerization, was measured using an Ubbelohde viscometer, and the obtained intrinsic viscosity of the polymer was 28.1 dL / g.

[0038] After replacing the prismatic flat blades with cylindrical blades of the same size, the intrinsic viscosity of the product was 28.1 dL / g. Although this was higher than the dual-blade combination in Comparative Example 3 and the single-blade combinations in Comparative Examples 1 and 2, it was still lower than the three-blade combination with a prismatic structure in Example 1. This further illustrates that the prismatic structure has a better shearing and mixing effect on high-viscosity materials than the cylindrical structure, and is more suitable for the mass transfer requirements of the PIPD polymerization system. This invention, through a specific prismatic structure and increasing the distance between the blade tip and the reactor wall, can quickly and efficiently throw the polymer climbing the pole in the later stage of polymerization onto the reactor wall through centrifugal force to achieve effective material blending.

[0039] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A polymerization reactor for preparing high molecular weight PIPD polymer, comprising a polymerization reactor body and a stirring paddle disposed within the polymerization reactor body, characterized in that, The impeller includes an agitator shaft, a prismatic flat blade impeller, a folding blade impeller, and a ribbon impeller; The stirring shaft is vertically arranged, and the prismatic flat blade and the folding blade are fixed on the stirring shaft from top to bottom and extend radially along the stirring shaft. The spiral blade is arranged in a spiral structure with the stirring shaft as the central axis and is located around the folding blade. The upper and lower ends of the spiral blade are connected to the stirring shaft through an upper fixed rod blade and a lower fixed rod blade, respectively. The upper fixed rod blade is located between the prismatic flat blade and the folding blade, and the lower fixed rod blade is located below the folding blade. The prismatic flat blade is a square cylinder with its cylindrical surface inclined relative to the plane of rotation; the folding blade is a sheet-like blade with its blade surface forming an angle of 40-60 degrees with the plane of rotation.

2. The method for preparing a polymerization reactor for preparing high molecular weight PIPD polymer according to claim 1, characterized in that, It also includes a power drive mechanism, which is connected to the stirring shaft to replace the rotation of the stirring shaft.

3. The method for preparing a polymerization reactor for preparing high molecular weight PIPD polymer according to claim 1, characterized in that, The prismatic flat blade has multiple blades, which are evenly distributed on the same plane of rotation.

4. The polymerization reactor for preparing high molecular weight PIPD polymer according to claim 1, characterized in that, The folding blade has multiple sets, which are distributed at intervals and staggered along the axial direction of the stirring shaft.

5. The polymerization reactor for preparing high molecular weight PIPD polymer according to claim 1, characterized in that, The ribbon impeller has multiple sets, and the multiple sets of ribbon impellers are arranged in a rotationally symmetrical manner with the stirring shaft as the central axis.

6. The polymerization reactor for preparing high molecular weight PIPD polymer according to claim 1, characterized in that, The three prismatic flat blades are evenly distributed on the same plane of rotation, with an included angle of 120 degrees between adjacent prismatic flat blades; the three sets of folding blades are distributed at intervals and staggered along the axial direction of the stirring shaft, with a staggered angle of 120 degrees; the three sets of ribbon blades are rotationally symmetrical about the stirring shaft.

7. The polymerization reactor for preparing high molecular weight PIPD polymer according to claim 6, characterized in that, The inner cavity of the polymerization reactor body is a cylinder with an inner diameter of Dr and a depth of H. Then: The outer diameter of the circle formed by the motion trajectory of the ribbon propeller when it rotates is 0.85-0.90 Dr, the height of the ribbon propeller is 0.8-0.85H, and the blade width of the ribbon propeller is 0.05-0.15Dr. The diameter of the circle formed by the motion trajectory of the folding blade when it rotates is 0.6-0.7Dr, and the blade width to length ratio of the folding blade is 0.12-0.22; the spacing between the three layers of folding blades is 0.20H, and the spacing between the uppermost folding blade and the upper fixed rod blade is 0.1H; The diameter of the circle formed by the motion trajectory of the prismatic flat blade propeller when it rotates is 0.4-0.5Dr, and the blade width to length ratio of the prismatic flat blade propeller is 0.18-0.25; the distance between the upper fixed rod propeller and the prismatic flat blade propeller is 0.15H.

8. The application of the polymerization reactor for preparing high molecular weight PIPD polymer according to any one of claims 1-7 in the preparation of high molecular weight PIPD polymer.

9. A method for preparing a high molecular weight PIPD polymer, characterized in that, The polymerization reactor for preparing the high molecular weight PIPD polymer according to any one of claims 1-7 specifically includes the following steps: TD salt, phosphorus pentoxide, and polyphosphoric acid were added to the polymerization reactor, along with tin powder as an initiator. The stirring paddle was started under an inert atmosphere, and the reaction was carried out by gradually increasing the temperature. After the reaction was completed, the stirring was stopped, and the polymer was removed from the reactor.

10. The preparation method according to claim 9, characterized in that, The reaction is carried out by heating in stages, specifically as follows: stir at room temperature for 10-30 min, heat to 100℃ and react for 0.5-1 h, then heat to 140℃ and react for 1-2 h, continue heating to 180℃ and react for 1-2 h, and finally cool down to below 120℃ and stop stirring. The stirring rate is set as follows: 350-250 r / min from room temperature to 100℃; 160-240 r / min from 100-140℃; and 120-150 r / min from 140-180℃.

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